1. Field of the Invention
The present invention relates to a human-computer interface for data entry, and more generally to the field of data processing. In particular, it relates to a device that is ergonomically designed with reference to the architecture and functions of the human hand, wrist, and arm.
2. Related Art
The development of ergonomically designed keyboards has resulted from an increased awareness and identification of physical problems associated with the use of conventional typewriterlike keyboards. An ergonomically designed keyboard attempts to create a key layout that reduces finger travel and fatigue; promotes a more natural hand, wrist, and arm typing posture through design and support structures; or employs various key activation schema in order to enhance typing performance.
Due to the proliferation and availability of data entry systems, there has been a dynamic growth in the use of keyboard devices. Various annoying and debilitating muscular syndromes have accompanied this expansion, resulting from the repetitive and fatiguing hand, wrist, and finger motions that are required in the use of conventional typewriterlike keyboards. There has been a growing concern over neuromuscular injuries among clerical workers, journalists, computer programmers, and others who use computers or typewriters extensively. These injuries, one widely publicized of which is carpal tunnel syndrome, translate not only into pain and potential disability for the affected users, but also into significant loss of money, time, and productivity for businesses. Attention to these problems is not new in the art, as is evidenced by many serious attempts to alleviate keyboard-use "injuries" through innovative keyboard layouts and architectural designs.
Force, repetition, posture, rest, and stress are major factors to be considered in controlling and eliminating keyboard-related injuries (KRIs). Analysis of each factor, both independently and in relation to one another, is necessary in designing a keyboard that eliminates or reduces KRIs, force and repetition being perhaps the most important in the development of an ergonomically designed keyboard. Force is related to the musculature and conformation of the fingers and hands, which place limitations on their ability to perform a given task.
An abundance of human-computer interaction literature has suggested that some of the recently developed alphanumeric input devices may be more efficient, easier to learn, and may cause less physical trauma than conventional typewriterlike keyboards. Of these recently designed keyboards, most incorporate one or more design features that enhance typing performance and reduce or eliminate fatigue or injury. These design features include: (1) splitting the keyboard to minimize wrist deviations; (2) key contouring and flexible key mapping to minimize finger travel; (3) built-in hand and arm support; (4) a ternary capability in which keys rock back and forth to type; (5) a capability to rotate and tilt the device into numerous positions; and (6) a chordal capability, in which more than one key must be depressed for a single character to be output.
In reference to eliminating or reducing force and repetition fatigue factors, three approaches taken in the prior art are illustrated in U.S. Pat. No. 4,332,493, issued to Einbinder, U.S. Pat. No. 4,849,732, issued to Dolenc, and U.S. Pat. No. 5,178,477, issued to Gambaro.
Einbinder discloses a typewriter keyboard in which the keys are arranged to conform to the "footprint" of the human hand. This layout of keys is designed with topographically height- and angle-differentiated actuation pads that attempt to minimize overall hand and finger motion. However, the Einbinder device stresses the importance of having "home positions" for the finger and thumb tips, from which position the fingers, and therefore the hands, must travel appreciably in order to perform typical typing operations. Thus, the Einbinder device eliminates only a portion of the problem in solving the motion difficulties encountered with conventional keyboards.
Similarly motivated by safety-related concerns, Dolenc teaches a one-hand key layout that includes a fanlike array of plural keys distributed in elongated rows and organized for specific actuation by the thumb and four fingers of the hand. Dolenc's device is concerned with minimizing hand motion, but not finger motion. In fact, Dolenc speaks in terms of organizing keys in arrays in such a fashion that they take into account the "motion and range of the respective fingers of the hand." Thus Dolenc clearly considers finger tip actuation of each key. While Dolenc seriously addresses the issue of minimizing hand motion, his system does not appreciably contribute to minimizing finger motion, nor to related wrist motion. In addition, this device does not address the angular and topographical distinctions for individual keys, such as those described in the Einbinder patent. Dolenc also does not establish a "home position" for the tips of the fingers and thumb as did Einbinder.
Gambaro discloses an ergonomically designed keyboard that is organized with an array of keys that are disposed generally "to complement the splayed underside architecture of the user's hand." A two-handed implementation is disclosed wherein each array includes, for each finger of the hand, a cluster of input keys that are placed in such a manner that they enable key actuation via only "slight, gestural, relatively closing motion of a portion of a confronting finger, and for the thumb in each hand." In addition, this design tries to overcome ergonomic problems with a set of keys disposed within two adjustable "hand-print"-shaped depressions. No appreciable movement of the fingers from the fingertip down to immediately below the first finger joint is required, each finger being capable of accessing four keys for the middle, ring, and little fingers, eight keys for the first finger, and a multitude of keys for the thumb. Again, even though drastically reduced, finger movement is still required, and all fingers are required for full key set actuation.
Other issued patents that address modified keyboard and character arrangements include U.S. Pat. No. 4,244,659, issued to Malt, U.S. Pat. No. 4,509,873, issued to Ryan, U.S. Pat. No. 4,579,470, issued to Casey, U.S. Pat. No. 4,597,681, issued to Hodges, U.S. Pat. No. 4,655,621, issued to Holden, U.S. Pat. No. 5,006,001, issued to Vulcano, U.S. Pat. No. 5,017,030, issued to Crews, U.S. Pat. No. 5,029,260, issued to Rollason, U.S. Pat. No. 5,067,834, issued to Szmanda, U.S. Pat. No. 5,087,910, issued to Guyot-Sionnest, and U.S. Pat. No. 5,137,384, issued to Spencer. None of these addresses the issues of keyboard use and motion injuries.
Computing devices are regularly used for relatively long periods of time by people of all ages and abilities, it is becoming increasingly important that a device also accommodate the physically challenged. Prior art devices in general demand considerable manual and digital dexterity to operate, making them difficult for some portion of the population to utilize efficiently and effectively.
Two types of hand rests, both for partial and full hand support, have been identified in the prior art. One kind acts as an actuator and is not intended to support a substantial part of the weight of the hand, but instead to impart some function. Another type of hand rest known in the art serves only to space the fingers from the proximity-actuated keys to avoid accidentally operating the keys.